Manufacture of sheets or boards containing mineral wool



UNITED STATES PATENT OFFICE MANUFACTURE OF SHEETS OR BOARDS CONTAININGMINERAL WOOL Albert L. Ciapp, Danvers, Mass.

No Drawing. Application May 9, 1938, Serial No. 206,840

10 Claims.

In my application Serial No. 185,784, filed January 19, 1938, of sheetsor boards c more especially long I have disclosed the manufactureontaining mineral wool and -fibered mineral wool by a process whichinvolves treating or soaking a mass of aggregated mineral or rock woolfibers, as it is available on the market, substantially uniformly with aslimy material and then manipulating the slime-treated or soaked mass inthe presence of water, as in a mixing or beater engine, to liberatesubstantially completely the fibers of the mass and thereby to sion ofthe substantially completely bers.

preserve largely or produce an aqueous suspenliberated fi- The mixing orbeater action is controlled to practically completely the originallength of the mineral wool fibers in the course of theirliberation andsuspension in water so that the resulting suspension mineral woolfibers, ranging contains the from a fraction of an inchto severalinches, constituting the starting mass of aggregated or tangled mineralwool fibers. 'Once the aqueous mineral wool fiber suspension isproduced,

and other purposes, p

cible binders, such as dispersions of bitume mixed therewith. In

mentioned application,

,it is possible to spread it for instance, to use it plaster forinsulating articularly when water-missodium silicate, aqueous n, resins,or the like, are adaccordance with the aforethe aqueous mineral woolfiber suspension is produced in a relatively large amount of water, foryield a suspension of instance, sufilcient water to about 3% to 4% fibercontent, and, alter further appropriate dilution with water, is formedinto making machine.

a shgt or board on a paper- ,1 As described in that application, it isfrequently desirable to produce an aqueous suspension of mineral woolfibers blended with cellulose fiber and/or asbestos or the like, inwhich case, the

slime-treated mineral wool fiber mass is added with proper manipulationto an already-prepared aqueous charge or. the cellulose fiber and/or toan already-prepared aqueous suspension of the asbestos fiber, as in abeater engine. The resulting aqueous suspension of mineral wool fiberblended with more asbestos fiber is then designed for various or lesscellulose and/or formed into sheets or boards purposes, for instance,for

use as thermo-lnsulating'material in buildings,

refrigerators, and other structures. finished sheets are to when the beused as wallboard or the like, they may contain a substantial proportionof both cellulose an d asbestos fiber as well as.

mineral wool fiber. However, should the quality of substantialfireproofriess be desired in the finished sheets or boards, they maycontain little, if any, cellulose fiber and be composed essentially ofthe mineral wool fiber or a blend of such fiber 5 and asbestos fiber. Insome instances, the finished sheets or boards may be impregnated withsizes or binders of various kinds, which, as disclosed in theaforementioned application, may be incorporated into the aqueous fibersuspension from which the sheets or boards are formed and/or be infusedinto the already-fabricated sheets or boards.

I have now ,found that when a slimy watersoluble soap solution is usedfor the purpocse of treating or soaking the mass of aggregated mineralwool fibers preparatory to the manipulation of the slime-treated mass inwater for the purpose of liberating the individual fibers of which themass is composed, it is distinctly advantageous that the water in whichsuch manipulation occurs contain a chemical reactive with theWater-soluble soap to form a water-insoluble soap gel or slime, for suchlatter gel or slime is even far more effective than a water-soluble soapslime in promoting the desired loosening and segregation or liberationof the individual fiber units from the mass and thereby yielding thedesired aqueous fiber suspension whose fibers are of a lengthapproximating those in the original mass 0 and which is practicallydevoid of clumps or tangled fibers. It will thus be seen that a slimywater-soluble soap solution is initially used so as to realize thedesired penetration and soaking of the mass of aggregated fibers, asthis ensures substantially uniform access of the slime to substantiallyall of the fiber surfaces. Once the fibers in the mass have beensubstantially uniformly enveloped or protected by the water-solublesoap, slime and the mass is to be manipulated in water, it is desirablethat the slime resist dispersion or difi'usion from the fiber surfacesinto the aqueous phase until fiber-liberation has been largelysubstantially completed; and this is accomplished pursuant to thepresent invention by converting the water-soluble soap slime on thefiber surfaces to a water-insoluble soap slimethrouglr the action ofsuitable chemicals present in thewater, namely, chemicals which furnishthe positive radical of a water-insoluble soap, for instance, 0chemicals of the nature of alkaline earth metal oxide or hydroxide,metal salts, etc. Lime, magnesium oxide or basic carbonate, orequivalent alkaline earth metal compounds are generally preferable byvirtue Ofthe fact that they render al- .mass, but it is preferable thatkaline the aqueous medium in which the slimetreated fiber mass is beingmanipulated. An alkaline medium evidently functions to preserve thestrength of the mineral wool fibers as they are being liberated from themass and hence minimizes cutting or fracture of the fibers, whereassalts, especially of an acidic nature, such as alum, although useful forthe purposes hereof, appear to weaken or tender the fibers as they arebeing liberated and hence to make more difficult the desiredpreservation of the fibers at substantially their original length.

While not limited thereto, the prese t invention will now be describedin terms of he manufacture of wallboard or insulating board containingasbestos and cellulose fiber. Any suitable cellulose fiber, such asgroundwood pulp, and suitable asbestos fiber, preferably short-fiberedasbestos, may be added to a beater engine in proportion to yield afinished sheet whose fibrous content will consist of, say, about 25% ofasbestos, about 25% of groundwood pulp, and about 50% of the mineralwool fiber. The groundwood pulp not only reduces the cost of the sheetbut serves, on account of its short fiber length, to improve its textureor formation. The short-fibered asbestos, which is also inexpensive, notonly improves sheet formation but assists to some extent in liberatingor individualizing the mineral wool fibers of the slime-treated mineralwool fiber mass subsequently added to the beater engine. The asbestosalso enhances the freeness of the stock even though it wets up andabsorbs water readily. The groundwood pulp and asbestos are mixed inample water in the beater engine until a substantially uniform aqueousfiber suspension is realized, whereupon about 5% of lime, calculated onall the fibrous components of the finished sheet or board (including theweight of the mineral wool fiber component subsequently added) isadmixed with the aqueous suspension of blended asbestos and groundwoodpulp.

The mineral wool fiber mass to be added to the fiber suspension in thebeater engine is prepared or conditioned for such addition by undergoinga substantially uniform wetting or soaking treatment with an aqueoussolution of water-soluble soap in slimy, preferably heated, condition.Specifically, a mass of the aggregated mineral wool fibers consisting offibers ranging from a fraction of an inch to several inches may bethoroughly soaked with excessive heated soap solution, such as a 3% to5% solution of sodium stearate or other fatty acid soap. The soapsolution may be produced by dissolving the soap in hot water, whereupon,while the soap solution is still hot or warm, the mass of mineral woolmay be submersed in an excess of the solution so as to ensure uniformwetting of substantially all the fiber surfaces with the solution. Thedesired results are had when about 200 parts of the mineral wool fibermass are plunged into about 1,000 parts of a hot soap solution of about3% to 5% strength. Excess soap solution may be drained and, if desired,gently squeezed from the upwards of about 150% tion upon being added ofits weight of soap soluto the beater engine. Upon being added to thebeater engine, which contains, for example, a lime water suspension ofthe asbestos and groundwood pulp, the soapsolution-soaked mass ofmineral wool fibers is subjected to manipulation and, in beingmanipulated, the lime water quickly diffuses to the soapy slimeenveloping the fibers and reacts the mass contain therewith to form awater-insoluble soap slime, namely, a, calcium soap slime. The calciumsoap slime resists, on account of its water-insolubility, displacementor dispersion from the mineral W001 fiber surfaces. Accordingly, suchslime tends to remain present on the 'fiber surfaces during themanipulation of the aggregated mineral wool fiber mass until the fibers,as a result of the continued manipulation of the mass, have beensubstantially completely liberated or individualized in the aqueousmedium and commingled with the asbestos and groundwood pulp fibers. Inother words, the calcium soap slime evidently affords the desiredlubricating action on the fibers and is not materially diluted ordispersed in the beater water until the fibers of the mass havesubstantially completely parted from one another and the originallyaggregated fibers of the mass have been resolved into individualized ordisaggregated fibers and have been substantially uniformly dispersedalong with the asbestos and groundwood pulp fibers in the aqueousmedium. The substantially complete liberation and dispersion of thmineral wool fibers in the aqueous medium requires only a comparativelyshort period of time, for instance, about 5 to 15 minutes or so, theparticular time depending, of course, on the particular mixing or beaterengine and the amount of stock charged thereinto. It might be noted thatthe mixing or beater engine used for the purposes hereof need not be ofthat type ordinarily used for papermaking, that is, the type comprisinga beater roll equipped with sharp blades or knives arranged infiber-cutting or beating relationship to a bed-plate. On the contrary,the mixing or beater engine used for the purposes hereof may comprise asits mixing or beating instrumentality nothing more than a paddle wheel,under whose action the desired or manipulate the mineral wool fiber massin the beater water. The same sort of manipulation, agitation, or mixingaction is also all that is usually necessary for slushing the asbestosand groundwood pulp to form a smooth fiber suspension. The finishedaqueous fiber suspension consisting of a blend of mineral wool fiber ofsubstantially original fiber length, asbestos, and groundwood pulp, maybe of about 3% stock or fiber content.

Once the mixed substantially completely individualized fiber suspensionhas been produced in the mixing or beater engine, various sizing agents,fillers, pigments, etc. may be added thereto. For instance, about 5% to8% cooked or raw starch, based on the dry weight of all the fibrouscomponents, may be added to the fiber suspension so as to enable therealization of a finished sheet or board of marked stiffness by reasonof its starch content. Again, alum in the amount of, say, about 2% to3%, based on the weight of the fibrous components, may be added to themixed fiber suspension so as to precipitate or fix on the fibers suchresidual lime and/or water-solublesoap as may have escaped interaction.It is generally preferable, however, to add alum in amount short ofimparting an acid condition to the fiber suspension, that is, in amountto leave the suspension at a pI-lf value of, say, 7.5 to 8.5,

for delivery to the papermaking machine. On its; way to the papermaking,or -board-forming. ma-

chine, the fiber suspension maybe diluted with further water toappropriate sheet-forming, or board-forming consistency; and, shouldthere be excessive foaming tendency in the suspension on account of itscontent of calcium fatty-acid soap, suitable anti-foaming agents, suchas kerosene and/or paraflin wax emulsion may be added thereto. Thesheets and/or boards may be formed on the papermaking machine in muchthe sameway and for much the same purposes asdisclosed in my applicationSerial No. 185,784; and the resulting sheets or boards may, if desired,undergosuch after-treatment or after-impregnation with suitable binder,waterproofing material, or the like, as disclosed in that application.

It is to be understood that the process hereof l is subject tovariation, so far as concerns, for example, such features as theparticular watersoluble soap slime used for soaking the mass of mineralwool fiber, the strength of the-aqueous water-soluble soap slime, the.particular fibrous composition orvfurnish'. for .the finished sheetl or1* board, and the particular kind of chemical used 1 toconvertthezwater-soluble soap slimezin-qthe' mineral'woot fiber massto'a'watereinsoluble soap slime, as it is being manipulated in waternGenei'al lyspeakingxit is preferable-.to' -u'se fatty-acid soap *slim'e'sof the natureof sodium 'stearate and/or sodium palr'nitate' and/orsodium .1 oleate or the like, but it is possible, ofacourse, to use thepotassium soap of the fatty acids or 'other"water-" J soluble"alkali-metal soap solution for initiallysoaking the mineral wool fibermass; Although rosin soap slime is not so effective as-fatty acid soapslime, yet it' may'be used in some instances, especially in admixturewith fatty acid'soap slime; Again, the soap of the substance knowncommercially as tallol, which is a by-product of kra'ft pulpmanufacture, may be used. Tallol soap, which may be prepared bysapo'nifying the tallol wlthalkali-metal hydroxide, such as sodium orpotassium hydroxide, is a complex material containing fatty acid soap aswell as rosin soap; and it may be used as a slimy aqueous solution ofsuitable strength for soaking the mass of mineral wool fibers. In lieuof forming the sheets or boards hereof from the particular mixed fibersuspension hereinbefore described, that is, a fiber mixture containingabout 50% of the mineral wool fibers and about 25% each of asbestos andgroundwood pulp, it is possible to'form such sheets or boards from anaqueous fiber suspension consisting essentially only of the mineral woolfiber or consisting of a mixture of the mineral wool fiber with, say,about an equal amount of asbestos. Again, it is possible to form thesheets or boards hereof from an aqueous suspension of mixed fiberscontaining, besides the mineral wool fiber, various proportions ofasbestos and cellulose fiber, for instance, chemical wood pulps, such askraft and/or sulphite pulp, waste papers, rag pulp, etc.; and, ifdesired, the mixed fiber suspension may contain animal fiber, such ascattle hair, wool, or the like.

It is to be understood that the process hereof constitutes essentiallyan improvement of the process outlined in my application Serial No.185,784, more especially in those instances when a water-soluble soapslime is used in initially treating or soaking the mass of mineral woolfiber, and that such improvement consists essentially in converting thewater-soluble soap slime into a water-insoluble soap slime by theaddition to the erated' fibers. 1

water in which the soaked fiber mass ismjanipu lated of a chemicalfurnishing the ion (i. e,, .positive alkaline earthmetal or'metal ion)combinable with fatty acid to yield water-insoluble fatty acid soap; Itis, as already indicated, preferable to 5 disseminate such chemical,.e;.g., lime, through-, out the water in the mixing or beating engine,before the addition and manipulation of the s'oapsolution-soaked mass ofmineral wool'fiber in the water, but such chemical; may be added to the'10, water simultaneously with the addition of such mass or during theveryearly stages of manipulating such mass in the water. ,Other than theparticular improvement herein indicated, the process hereof is akin tothe process of theaforementioned application andmay involve the variousfeatures indicated in that application Iclaim: r u

1. A process which comprises treating almass ous slimeof water-solubleso'apgof at least about- 3%.soa'p content so-astoenvelop;the'fibersgsubj w v 1 stantial-ly 'uniforrnlyw ith, theslimegandagit stantiall-y completely-liner suspension die the subsntiall of at least a ut 3% soap,;co'ritent streamin ,suchslime-treatedmass of. aggregated fibers in I water containing a chemicalthat reacts with'sai d soap and forms a' water-insolublesoap slime untilthe fibers of said mass have been substantially completely liberatedtoyield an aqueous suspension of the substantially completely liberated 403. A process which comprises treatinga mass of aggregated mineralwoolfibers with aqueousslirne of water-soluble soap in amount infexcess ofthat'- necessary to envelop the fibers substantially unifo'rmly with theslime; removing excess slime from said mass; and agitating saidslimetreated mass in lime water, thereby converting said slime intocalcium soap slime, until the fibers of said mass have beensubstantially completely liberated to 5 yield an aqueous suspension ofthe substantially completely liberated fibers.

4. A process which comprises thoroughly soaking a mass of aggregatedmineral wool fiber with aqueous slime of water-soluble soap in amount 5in excess of that necessary to envelop the fiber substantiallyuniformly; removing excess. slime from said mass; and agitating saidslime-soaked mass in lime water, thereby converting said slime intocalcium soap slime, until the fibers-of said 60 mass have beensubstantially completely liberated to yield an aqueous suspension of thesubstantially completely liberated fibers, said agitation beingcontrolled to preserve largely the original fiber length of said fibers.

5. A process which comprises treating a mass 'of aggregated mineral woolfibers with aqueous slime of water-soluble soap of at least about 3%soap content in amount in excess of that necessary to envelop thefiberssubstanti ally uniformly with the slime; removing excess slimefrom said mass; adding the slime-treated mass to an already-preparedsuspension of asbestos and cellulose fiber in water containing achemical that reacts with said soap and forms a water-insolan aqueousslime of'water'esolub fatty-acid 15 4 uble soap slime; agitating saidmass in said water to liberate substantially completely the fibers ofsaid mass and thereby to produce an aqueous slime of water-soluble soapin'amount in excess' of that necessary to envelop the fiberssubstantially uniformly with the slime; removing excess slime from saidmass; adding the slime-treated mass to an'already-prepared suspension ofasbestos fiber in water containing a chemical that reacts with said soapand forms a water-insoluble soap slime; agitating said mass in saidwater to liberate substantially completely the fibers of said mass andthereby to produce an aqueous suspension of thesubstantially completelyliberated fibers, said agitation being controlled to preserve largelythe original fiber length of said mineral wool fibers; and sheeting themixed fibers from the resulting aqueous suspension.

7. A process which comprises treating a mass of aggregated mineral woolfibers with aqueous slime of water-soluble soap in amount in excess ofthat necessary to envelop the fibers substantially uniformly with theslime; removing excess slime from said mass; adding the slime-treatedmass to an already-prepared suspension of cellulose fiber in watercontaining a chemical that reacts with said soap and forms awater-insoluble soap slime; agitating said mass in said water toliberate substantially completely the fibers of said mass and thereby toproduce an aqueous suspension of the substantially completely liberatedfibers, said agitation being controlled to preserve largely the originalfiber length of said mineral wool fibers; and sheeting the mixed fibersfrom the resulting aqueous suspension.

8. A process which comprises thoroughly soaking a mass of aggregatedmineral wool fiber with aqueous slime of at least about 3% concentrationof water-soluble fatty acid soap in amount in excess of that necessaryto envelop the fiber substantially uniformly; removing excess slime froming a mass of aggregated mineral wool fiber with aqueous slime ofwater-soluble fatty acid soap in amount in excess of that necessary toenvelop the fiber substantially uniformly; removing excess slime fromsaid mass; adding the slimesoaked mass to an already-prepared suspensionof asbestos in lime water, thereby converting said slime into calciumfatty acid soap slime; agitating said mass in said water to liberatesubstantially completely the fibers of said mass and thereby to producean aqueous suspension of the substantially completely liberated fibers,said agitation being controlled to preserve largely the original fiberlength of said mineral wool fibers; and sheeting the mixed fibers fromthe resulting aqueous suspension.

10. A process which comprises thoroughly soaking a mass of aggregatedmineral wool fiber with aqueousslime of water-soluble fatty acid soap inamount in excess of that necessary to envelop the fiber substantiallyuniformly; removing excess slime from said mass; adding the slime-soakedmass to an already-prepared sus-' pension of cellulose fiber in watercontaining lime, thereby converting said slime into calcium fatty acidsoap slime; agitating said mass in said water to liberate substantiallycompletely the fibers of said mass and thereby to produce an aqueoussuspension of the substantially completely liberated fibers, saidagitation being controlled to preserve largely the original fiber lengthof said mineral wool fibers; and sheeting the mixed fibers from theresulting aqueous suspension.

' ALBERT L. CLAPP.

as I

